Such apparatus as described above is particularly suitable for interconnecting a pair of opposed pistons with a crankshaft throw in positive fluid displacement machines such as pumps and internal combustion engines as proposed for example in EP-A 0,241,243.
A problem in such known apparatus is to ensure adequate lubrication the planar guide surfaces under the high loads imposed on them particularly at high speeds.
Apparatus according to the invention is characterised in that the bearing port or ports connected with a guide surface lie within a quadrant of the plain bearing, the two quadrants being on opposite sides of the axis of the bearing, and the outlet ports in the eccentric portion all lie in a sector thereof smaller than the angular extent of the unported portion of the bearing separating ports connected to different guide surfaces of the drive block.